Dirk Hammond, private detective, is called to the mansion of Baron Cardula. Grisly murders are sweeping San Francisco, and the Baron fears he will be next. Lured by $50, 000 and the Baron's fiery daughter, Hammond agrees to take the case. The dark trail leads him to a pack of blood-thirsty vampires, a diabolical cult of devil worshipers, and in a terrifying finale he is forced to confront Evil itself.